Marine derrick structure



April 13, 1937.

V. F. GRACE ET AL MARINE DERRICK STRUCTURE Filed Aug. 17, 1954 2Shets-Sheet 1 Inventor TZ'CZOZE/ Grace WaZterHRz'chardson Attorney '2Shets-Sheet? v. F. GRACE ET AL Filed Aug. 17, 1934 MARINE DERR ICKSTRUCTURE April 13, 1937.

Inventor WalzerH Richardson /1 ttorncy m r w W arrangement of the pilesin the foundation struc- Pa'tented Apr. 13, 1937 UNITED STATES j PATENTOFFICE Victor F. Grace, zefi ie vzfi mma.

son, s Angeics, Calif., assignors to General Petroleum Corporation ofCalifornia, a corporation of Delaware Application August 17, 1934,Serial No. 746,282 -3 Claims. (or. s -4s) This invention has to do in ageneral way with oil well drilling operations and is more particularlyrelated to the so-called "marine" oil well derrick structures such asare used in drilling 5 and producing oil from submarine formations atsubstantial distances from the shoreline and in considerable depths ofwater.

As is well known to those famfliar with the art, the production of oilfrom submarine foro mations is practiced to quite a great extent, par-In certain prior structures with'which we are familiar, it is thepractice to employ a foundation structure consisting of a system ofvertical piles or piers positioned beneath the corners of the derrickfloor and symmetrically arranged about a centrally disposed caisson, thepiers and the caisson all being supported on the shale of the oceanfloor. This caisson constitutes a con- 'tainer for a conductor pipe andthe various casings employed in drilling the well. It also constitutes asupport for a tank or sump winch must be provided in order to preventcontamination of the ocean water with oil and drilling fluid which isalways thrown upon a derrick floor from time totime during drillingoperations.

Due to the enormous expense involved in building a caisson of the typeemployed in these prior structures, it becomes the primary object ofthis invention to provide a derrick foundation of the class describedwhich does not employ a caisson. In the structure contemplated by thisinvention we employ what may be termed a substantially open foundationstructure formed by four sets of parallel piles, the piles preferablybeing driven into the formation at an angle with the vertical so thatthe four sets converge at their upper ends to form the edges of arectangle or square which constitutes the support for the derrick floor.The

ture contemplatedby this invention may be described as the frustum of anopen pyramid. It is an important feature. of this invention that thesump or drainage tank is supported directly from the same piles whichcarry the derrick structure. There is no caisson, nor is there anysubstructure enclosed within thesystem of piles for (the purpose ofsupporting the tank. We havediscovered that it is not necessary toemploy a caisson but that the conductor pipe may be extended directlydown through an opening in the bottom of the tank and into the formationinto which the well is drilled.

' Inasmuch as the conductor pipe and the first string of casing, used inthe structure contemplated by this invention, are cemented into theformation to quite a great depth, and constitute the sole support forthe remainder of the casing used in the well, whereby the derrick andits foundation is relieved of .the tremendous weight of the casingsextending into the well. we consider it important that the conductorpipe and the tank through which it extends be adapted to have relativemovement with respect to eaohother. In other. words, the derrick and thewell casings are independently supported. With this in mind we employ asealing means between the conductor pipe and the opening in the tankwhich will permit such relative move ment. This sealing means in thepreferredform of our invention comprises a stuffing box.

In various structures of this nature it is necessary that a tightsub-floor or drainage floor be positioned below the derrick floor andabove the top of the tank for the purpose of draining oil and drillingfluid into the tank. It is an important feature of the structurecontemplated by this invention that this sub-floor, which we willhereinafter refer to as a "dished floor, is supported entirely by thesame piling system which carries the derrick structure. I

It is the principal object of this invention to provide a foundationstructure of the class described which is of simple form andconstruction and which may be erected at a considerable saving over thetypes nowin use.

The details in the construction. of a preferred form of our invention,together with other objects attending its production, will be bestunderstood from the following description of the accompanying drawings,which are chosen for illustrative purposes only, and in which Fig. 1- isan elevational view showing a foundation structure of the typecontemplated by this invention and illustrating the manner in which thesame supports an oil well derrick;

Fig. 2 is a sectional elevation taken in a plane represented by the line2-2 of Fig. 1;

Fig. 3 is a plan section taken in a plane represented by the line 33 ofFig. 2

, Fig. 4 is a plan section taken in a plane represented by the line 4-4of Fig. 2

Fig. 5 is a plan section taken along the line 6-5 of Fig. 2;

Fig. 61s an enlarged fragmentary section illustrating a preferred formof hanger used in supporting the tank from the derrick supporting means;and

5 Fig. 7 is an enlarged fragmentary section taken along the line 1-1 ofFig. 2 and illustrating one cates a foundation structure which consistsof a plurality of piles l2, shown as being arranged in four sets orpanels, the individual piles in each set or panel being parallel witheach other, and the four sets of piles being arranged to form the sidesof the frustum of an open pyramid. In other words, the four sets orpanels of piles converge at their upper ends to define a rectangle orsquare as clearly illustrated in Fig. 3.

The top of the piles are provided with plates generally indicated at isand I3, such plates supporting beam members I which are secured to theplates l3, l3 and to cross beams I5, Ii.

These beam members constitute a supporting frame structure which carriesthe derrick, generally indicated at I 6, and the derrick floor I1 whichin turn supports the drilling machinery.

As has previously beenpointed out, it is an important feature of thisinvention that the system of piles just described constitutes the onlyfoundation or supporting structure which is posi-v tioned beneath thederrick. It was also previously pointed out that it is necessary, insubmarine derrick structures, to provide a drainage tank which issituated beneath the derrick floor. Such a tank is indicated by.reference numeral l9 and is shown as being supported from the framestructure made up of-beams l5 and II through the medium of hangers 20which are secured by means of welding or in any other suitable manner attheir upper ends to the beams of the frame structure and are secured attheir lower ends to the tank. In thisform of our invention this latterattachment is made by notching the lower ends of the hangers 20, asclearly shownin Fig. 6, so that the notched portions receive the edge ofthe tank I9, and then welding or otherwise securing the edge of the tankto the notched portion .of the hanger 20.

The bottom of the tank is preferably made in the form of a square plate2|, which makes for convenient attachment to diagonal braces 22extending from the bottom of the tank to what we may termcross braces 23which are shown as being positioned between adjacent corner piles in aplane at or near the plane of the bottom of the tank. In addition to thecross braces, 23 we provide a series of cross braces between each pairof piles as indicated at 23' so that the complete system of piles isrigidly braced at a point between the mean water level L and the top ofthe foundation structure.

The bottom 2| of the tank is provided with an 05 opening 26 throughwhich a conductor pipe 21 is driven through the sand 28 into the shale29. The use of such a conductor pipe is conventional in oil welldrilling practice,'both on land and over water operations. Thisconductor pipe is cemented into the formationand the drilling operationtakes place therethrough in the manner well known to those familiar withthe art.

Since the conductor pipe and the first string of casing S1 containedtherein constitute the sole support for the remainder of the casing(generally indicatedat 8:) extended into the well, as the drilling.operations proceed, and since the tank I8 is supported by the piling orfoundation structure which carries the derrick, we consider itpreferable that some latitude be allowed for relative 5 movement betweenthe conductorpipe and the tank due to possible difierences in settlingover an extended period of time. with this in mind, instead of weldingor rigidly sealing the bottom of the tank to the conductor pipe, wepropose to 10 use some type of sealing means which will permit suchrelative movement. One form of such sealing means is shown as comprisinga stuillng box, generally indicated by reference numeral II.

In conjunction with the tank I! it is necessary 1 to employ a sub-flooror drainage floor which will convey any oil or drilling fluid that mayleak through the cracks in the derrick fioor directly into the tank ii.In this form of our invention we construct the sub-floor by welding orother- 20 wise securing an outer frame 32 to the inner surface of thepiling system. An inner frame member 33 is supported by the upper edgeof the tank is and diagonal brace members 34 are interposed between thecorners of the inner and outer frame 2.5 members. It will be observedfrom Fig. 2 that the outer frame member is placed at a slightly higherelevation than the inner frame member so that the diagonal braces extenddownwardly from the outer edge of the foundation structure to the upperedge of the tank. Joist members 36 are then positioned between the outerand inner frame members and the diagonal braces 34, such joist membersconstituting the support for a tight floor which is generally indicatedby refer- 35 ence numeral 31. The construction of this floor is perhapsbest illustrated in Figs. 2 and 4.

, Any conventional means may be employed for withdrawing the contents ofthe tank H. In the illustration we have shown the tank as being 40provided with a drain pipe 38 which extends to' a suitable sump or pump,not shown, that may be located at some point on the pier or on theshore.

It will be apparent to those familiar with the art that the type ofstructural members employed, 45 and the particular shape defined by thepiers or piles which constitute the foundation, can be varied. to suitthe particular conditions at the location of the derrick structure. Weprefer to employ tubular metal piles and, at all points 50 where it ispossible, make the connections between the various structural elementsby means of weld- It is to be understood that, while we have hereindescribed and illustrated one preferred form of our invention, theinvention is not limited to the preciseconstruction described herein butincludes within its scope whatever changes fairly come within the spiritof the appended claims. 60

We claim as our invention:

1. In a marine derrick structure the combinatipn of: a plurality ofpiles arranged to support a derrick a plurality of horizontalbeams'mounted on said piles to form a supporting structure: 5 hangerssuspended from said supporting structure; and a tank supported by saidhangers.

2. In a marine derrick structure, the combi-' nation of: a plurality ofpiles arranged to support a derrick; a derrick supporting frame mount- 7ed on said piles; hangers suspended from said frame; a tank supported bysaid hangers, said tank having an opening in its bottom; a conductorpipe extending through said "opening; and sealing means in said openingsurrounding said 75' conductor pipe, said sealing means being of anature such as to permit relative movement between said tank and saidconductor pipe.

3. In a marine derrick structure, the combination of: a plurality ofpiles arranged to support a derrick; a. derrick supporting frame mountedon said piles; hangers suspended from said frame;

a tank supported by said hangers, said tank having an opening in itsbottom; a conductor pipe extending through said opening; and a stufiingbox in said opening surrounding said conductor pipe.

VICTOR F. GRACE. WALTERH. RICHARDSON.

